WHO has published MERS-CoV summary and literature update – as of 20 June 2013. This is one of the most extensive reports WHO has issued so far. Excerpt:
Although the exact timing and nature of exposures that result in infection is usually unknown, for those cases for which exposure is known or strongly suspected, the incubation period for laboratory confirmed cases of MERS-CoV is generally less than one week.
However, in at least one case the known exposure occurred 9 to 12 days prior to onset of illness. Further evidence in cases exposed over a range of time suggests that, at least in a minority of cases, the incubation period may exceed one week but is less than two weeks.
Evidence is also accumulating to suggest that nasopharyngeal swabs are less sensitive for detecting infection with MERS-CoV than specimens taken from the lower respiratory track. Currently, no head-to-head comparisons are available on the two approaches to diagnosis.
However, in a number of patients, NP swabs have been negative at one point during the course of illness while lower respiratory specimens were positive at another time during the same illness. In addition, in several clusters, patients who were strongly suspected of having MERS-CoV infection because of direct exposure and severe respiratory illness had NP swabs that tested negative, while other confirmed cases in the cluster had lower respiratory track specimens that tested positive.
